Blr243 wrote:And for that I mean for a case like my 243 that has a shoulder. A 45 acp headspace is measured from the case mouth back to the bolt face because it’s the case mouth that stops the case being chambered too deep. So I think people who crimp the mouths too much on their acp may be messing with their headspace a bit. Not sure. Have not loaded for pistol in over a decade For safety and for case life and for perhaps accuracy I like to size my cases in my 243 so that I can feel a slight compression as I close the bolt completely. Then I know it’s tight and there’s no slop slop. It just feels right to me
Yeh, that slop is head space for a rimless case.
For a rimmed case its the gap from the bolt to rim.
Bloody text. Often hard to explain.